Method of treating porous and fibrous material.



G. D. BURTON. METHOD OF TREATING POROUS AND FIBROUS MATERIAL.

APPLICATION FILED SEPT. 24, 1912.

Patented Dec. 29,1914.

GEORGE D. BURTON, 015 BOSTON, MASSACHUSETTS, ASSIGNOR TO THE IBURTON COM- PANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

METHOD OF TREATING-POROUS AND FIBEOUS MATERIAL.

Specification of Letters Patent.

Patented Dec; 29, 191d.

Application filed September 24, 1912. Serial No. 722,047.

pulp, and is particularly adapted for pulping corn stalks, rice and flax straw, grasses, and the like, although it is not restricted to such use, but may be employed for digesting any sort of pulp material.

An apparatus suitable for carrying out the method is shown in the accompanying drawings and described in detail in the following specification, although I declare that I do not restrict my invention to the exact form and construction there shown and described, but include within the scope thereof any forms of apparatus capable of obtaining substantially the same results in substantially the same or an equivalent manner.

In the accompanying drawings, Figure 1 is a plan view of the apparatus embodying the features of the present invention. Fig. 2 is a longitudinal sectional view of the same. Fig. 3 is a cross section of the same. Fig. 4

is an elevation bf the right hand end. Fig. 5 v

is a sectional view showing a detail of construction of the apparatus. Fig. 6 is a detail elevation and Fig. 7 a perspective view of an electrode employed as a part of the apparatus in carrying out the process effect ed by the apparatus. I.

The same reference characters indicate the same parts in all the .fig'ures.

T will first describe the apparatus illustrated, and then explain the steps of the method in which the invention particularl resides, and in the carrying out of whic this apparatus is used.

The apparatus includes in its construction a stationary outer shell 1 and a revoluble inner shell 2, the former being water tight except for the openings hereinafter described and the latter being perforated in its cylindrical walls and having perforated transverse partitions 3, as shown in Fig. 2. The outer shell is secured in a stationary condition-upon sup orts i, a and has in its upper side a num er of manholes 5,, one

being over each of the compartments of the inner shell, such manholes being tightly closed by removal covers 6. In the ends of the outer shell are packed bearings 7 which contain rotatably the trunnions 8 which pro ect from the heads of the inner shell, and through these trunnions there. passes a shaft 9 to which the inner shell is secured. Said shaft is additionally supported by bearings 10, 11 and carries gear wheels 13, ltwlnch mesh with pinion gears 15, 16 on a driving shaft 17. The latter carries also a gear 18 in mesh with a pinion 19 on a coun tor-shaft 20 upon which latter are also secured tight pulleys 21 22 and a loose pulley 23 adapted to be engaged alternately by belts 24, 25 passing over pulleys on a shaft 26. These belts drive in opposite directions and are shifted from time to time by a shipper mechanism 27. Thereby the inner shell is rotated for a number of turns, first in one direction and then in the other. A pipe 28 is connected at a number of points with the outer shell and serves to admit steam or a pulping solution to be used in carrying out the pulping process. Another pipe 29 is also connected with the outer shell at the bottom thereof for drawing off the solutions therefrom. A pipe 30 is connected with the shell preferably at the top thereof for admitting water and solutions thereto. All of these pipes are provided with valves by which communication through them may be made and interrupted. There are also pipes 31 and 32 leadi from the upper part of the outer shell to a trap 33, which latter communicates with a condenser, consisting conventionally of a ipe coil 34 in a tank 35 through which coo ing liquid may flow. These pipes are also provided with valves whereby either or both may be opened or closed.

I provide means for directing an electric current through the solution in the digester atsuch times as the digesting process requires. Such means comprises electrodes 36 and 37, indicated in dotted lines in Fig. 2, which are mounted at widely separated points in the outer shell and are connected with conductors 38 and 39, which carry an electric current from a source of sup ly through a switch 40.. One of the electrodes, which is typical of both, is shown in detail in Figs 6 and 7. Said electrode is an aluminum bar 41 of suitable dimensions and.

mass for the current handled, which is sup-' ported at or near its ends in chairs 42 of any suitable insulating material, such as desired points in the shell near the electrodes, whether in the ends or sides of the shell being immaterial, as the shell is stationary. A preferred form of insulating plug is shown in Fig. 5 and consists of a threaded tube 4A screwed intothe shell 1, having a bore considerably larger than the conductor, which conductor is held centrally by a mass of insulating material 45.

Having described the construction of my pulp digester'indetaiL-I will now describe my improved method .of producing pulp from cornstalks, straw, grass, etc.

The ingredients of the pulp, whether the same is corn-stalk, rice or flax straw, cotton stalk, or any other porous and fibrous materials, mixed or separate, are put in the inner cylinder with a saponaceous solution of a strength approximately from 3 to 5 per cent, more or less, or equivalent washing liquor, for the purpose of washing out dust, earth, the black or creosote joint in the corn stalk, also the seeds or grains and tassel of the corn, rice, flax, etc., and any other deleterious substances which'may be min- 'gled with the stalksor straw. The driving machinery is set in operation and the inner drum is thereby revolved first in one direction and then in the other, lifting and dropping the mass of pulp material and 'subjecting it to thorough washing. The-perforations in the inner drum are sufficiently large to allow the dirt, seeds, and kernels of grain to pass through, whereby they may be drawn off through the outlet pipe 29 with the washing solution. In the pulping of the materials named the removal of dirt, seeds, etc., is essential to the production of clean pulp, and this character of digester accomplishes such removal completely and perfectly. More particularly in the treatment of flax straw, the removal of the flax seeds is essential. After their' removal, as described, these seeds are drawn off, washed and dried, andbecome a useful and valuable by-product. The same is also true in regard to rice grain in the treatment of rice straw.

Sometimes there is a considerable quantity of flax seed or rice kernels in the straw, coming from hea swhich were greenfwhen the straw was t reshed. but subse uently ripened as the straw was dried. ll the seeds or kernels remaining in the straw'after drying preliminary to the pulping operation become dislodged readily during the agitation and pass through the perforations and are withdrawn. 'This same method is eflecas well as dirt and coloring matter in the same. After the washing is completed and the washing solution is drawn ofi, any

proper dissolving or digesting solution is admitted to the digester without necessitating removal of the stalks. The same agitation is effected by the revolution of the inner drum back and forth when at the same time, if required, steam may be introduced through the pipe 28. Any suitable digesting solution which is best adapted to the substance under treatment may be employed in this operation. The electrodes and the electric circuit described are used in this process, when desired, for .purposes either of heating or of electrolysis of. the solution or both. The solution between the electrodes completes the circuit, and this solution is both heated by the current and somewhat decomposed. The elements produced by electrolysis air in digesting and in bleaching the pulp, the latter effect being accom plished by the nascent oxygen so produced. When the pulping operation is complete, the mass is sufliciently fluid to flow through the perforations in the inner drum and to be drawn off from the outlet pipe 29.

Sometimes weeds are cut with the stalks and dried with them. Such weeds are automatically'separated from the pulp whenthe digestion of the latter is-complete, because they do not dissolve when subjected to the pulping solution required for stalks and straw, and therefore when the pulp passes from the digester, the weeds remain inside the inner cylinder and may be removed when desired. It is of. great advanta e in the production of good clean pulp rom stalks, straws, etc., that weeds be entirely eliminated. This apparatus enables complete separation' of "the weeds to be effected, and is the onl one of which I halve-knowledge capable o securing this resu t.

The machine, may be made of any mate metaland partly of wood, or of any other material. Where the machine is entirel of metal, I avoid danger of short circuit 0 the electric current through the machine itself,

rial, either entirely of metal or partly of,

Manatee verses, and then to be picked up in the op-- posite direction. This drop of the pulp and its carriage in opposite directions tends to beat up the substance and force out the dirt particles, seeds, etc., and in the digest ing process to quickly and thoroughly mingle the solution with the pulp. Thus in both steps of the process, the desired results are eifected more rapidly than is possible with other machines.

T have found that by means of this apparatus and the process with which it is used, I can take a mixture from onc-half'to twothirds corn stalks and one-third to one-half waste flax straw, or other stalks, grasses, or straws, and produce a high quality of pulp of good length and strength, which can be manufactured into leather board, card board, or paper, and molded or pressed into any desired shape. The pith of the corn stalk makes a good filler for the pulp when mixed with the fibrous materials mentioned, or others. The apparatus also enables the alcohol distilled from the vegetable matter by the pulping process to be collected and saved. The alcohol and other vapors in the upper part of the shells are allowed to pass through the pipes 31 and 32'to the condenser, from which they are drawn in liquid condition for further treatment.

From the foregoing description it will be seen that I have provided an efficient apparatus for separating dirt, seeds, etc, from corn and other stalks and straws, for converting such stalks and straws rapidly into pulp and bleaching the pulp, for separating weeds from the pulp,and for reclaiming alcohol, The stalks or straw may be put into the inner shell or container whole,'thatis, without being cut into short lengths, and just as they come from the field after being dried, thatis, with the weeds and any other porous substances or material that may be mixed with them. The washing and digesting steps of the process carried out while the material remains in the inner perforated container, as above described, enable all these foreign things or substances tobe completely and elfectively separated from the pulp which is finally obtained from the material. The pulp secured as the finished product has along fiber and is homogeneous in character, being thereby very tough and strong, and having the qualities necessary to produce high grade paper.

My process saves more than half the time now required by other methods, and saves labor and produces a better, cleaner, and stronger pul i The washln solution which ll consider best adapted for the purpose of removing dirt and other foreign substances contains borax, sal soda, liquid ammonia, and soap chips, all dissolved and mixed together.

- The salts mentioned serve to dissolve the silica which forms the protective coveringof corn stalks and straw, removing the sili- -c1ous covering, which, if left in the pulp,

would cause the paper made therefrom to be stiff and brittle. The dissolving or digesting solution used in the latter step is preferably a solution containing sufiicient caustic soda to bring its specific gravity from approximately 1.010 to 1.015 more or less.

I wish to be understood in the operation of this invention that I may do so with or without the use of a current of electricity, but when a current of electricity is used I usually employ a current which may be obtained from any suitable source and may vary in volume and pressure from 7 5 to 500 volts and from 6 to 200 amperes, more or less, according to the size of the apparatus and the quantity of the material it is desired to treat at one operation.

I claim:

1. The method of converting fibrous ma terial into pulp which consists in placing the material in a perforated container, revolving said container in a saponaceous solution until foreign "matter has been removed from the material and carried through the perforations of the container,

and then rotating the container in a dissolving solution until the material is sufficiently digested to pass through the perforations of the container.

2. The method of converting fibrous vegetable matter into pulp which consists in placingthe vegetable matter in a perforated container, agitating said container in a soap solution until such foreign matter as is attacked by such solution has been removed from the material and has passed out of the container, then agitating the container in a digestingsolution containing causticsoda or a substance having an equivalent action, and then separating indigestible weeds from the fibrous pulp material by causing the digested pulp to pass through the perforations of the container.

3. A method of pulping material which consists in placing the material in a perforated container, rotating said container in the solution containing a mixture of dis solved borax, sal soda, soap chips and ammonia to a strength of approximately from three to five per cent, until the dirt, seeds, and other foreign matter commingled with a the material have passed through the perforationsof the container and then similarly rotating the container in a digesting or dissolving solution .containing caustic soda in suflicient quantity to bring its specific gravity from approximately 1.010 to 1.015, until the material is sufficiently digested to pass through the perforations of said container.

1. The method of converting corn stalks into pulp which consists in placing the entire corn stalks as they come from the field in a suitable perforated container, revolving said container, in a saponaceous solution until dirt, kernels, the silicious coating of the stalks and other foreign substances have been removed from the stalks and carried through the perforations of the container, then rotating the container in a. dissolving solution containing caustic soda or equivalent agent, and then separating weeds from the stalks by causing the digested stalks to pass through the perforations. 1

5. Method of making pulp from such materials as cornstalks, straws, grasses, etc., which consists in placing said material'in a perforated cylinder, revolving said cylinder within another receptacle containing a suitable cleansing solution, for the purpose of eliminating the seeds, dirt, etc., and then removing the Waste substance from the outer cylinder, recharging the outer receptacle with a pulping solution, for the purpose of reducing the said materials to a I pulpy condition.

6. The method of treating porous. and fibrous substances for the purpose of removing the deleterious elements contained therein, so that the same may become useful in the arts and trades, which consists in nating the undesirable substances contained therein, which consists of placing the material to be treated in aperforated cylinder revoluble in a tank or vat containing a cleansing solution, revolving the cylinder a number of turns first in one, and then in the opposite direction, then withdrawing the saturated cleansing solution and adding a different solution and continuing the treating of the material until the same becomes a useful commodity.

8. The method of treating porous and fibrous substances containing seeds, which consists of placing the material in a perforated cylinder revoluble in a tank containing a suitable treating solution for the purpose of Washing out the seeds, dirt, etc., and passing the same off through the apertures in the revoluble cylinder by revolving said cylinder in the tank and then subjects ing the remainingmaterial in the cylinder to further treatment for the purpose of pulping said material.

in testimony whereof I have afiixed my signature, i'n'presence of two Witnesses.

GEO. D. BURTON. 4

Witnesses:

P. W. Pnizn'r'rr, G. L. JoHNsoN. 

